# 蓝桥杯18 A一
# z = 0
# m = 0
# x = 10
# change = 0
# for n in range(10, 100):
#     if n == 10:
#         z = 1
#         m = 0
#     else:
#         z = n // 10
#         m = n % 10
#         if z == (m + z) * 2 // 10 and m == (m + z) * 2 % 10:
#             change += 1
# print(change)

# 蓝桥杯18 B一
# a = set()
# b = set()
# c = set()
# for i in range(1, 1001):
#     if i % 3 == 0:
#         a.add(i)  # 遍历完成时拿到第一次所有关了的灯
#     if i % 5 == 0:
#         b.add(i)  # 遍历完成时拿到第二次所有关了的灯
#     if i % 7 == 0:
#         c.add(i)  # 遍历完成时拿到第三次所有关了的灯
# d = a ^ b#目前又关了的灯的序号
# e = d^c
# print(1000-len(e))



# 2018A模拟赛一 数列求值 #！此题未完成！！！
# a = []
# n = int(input())
# A, B = map(float, input().split())
# a[:0] = map(float, input().split())
# w=0

# A第一项 B为最后一项
# def numsum(n, x=0) -> float:
#     for i in range(n, -1, -1):
#         if i == 0:
#             x += A
#             return x
#         elif i == n + 1:
#             x += B
#         else:
#             return numsum(n - 1) / 2 + numsum(n + 1) / 2 - a[n-1]
# q=float(n*A+B)
# for i in range(n,0,-1):
#     r=i*a[len(a)-n]
#     w+=r
# t=float(q-2*w)
# o=float(t/(n+1))
# print("%.2f"%o)


#购物清单 纯计算
#print(696.21*0.58+438.12*0.65+345.48*0.68+610.31*0.75+563.35*0.78+278.44*0.7
# +830.36*0.88+1157.28*0.8+329.24*0.95+545.74*0.9+1321.63*0.5)


#acm原题
#计蒜客A1002
# def str_len(s):
#     x=0
#     for i in s :
#         x+=1
#     return x
# s =input()
# print(str_len(s))

#计蒜客A1001
# a,b=map(int,input().split())
# if 1<=a<=500 and 1<=b<=500:
#     if a%b==0:
#         print("YES")
#     else:
#       print("NO")
















































